The invention relates to a system for diagnosing equipment. In particular, the invention relates to a diagnostic support system and a diagnostic system capable of judging the conditions of semiconductor manufacturing equipment based on operating states of the equipment.
Using a technique for diagnosing manufacturing equipment, data considered to be relevant to abnormalities and failures of the equipment to be diagnosed is measured and then processed in order to obtain quantities which serve as indicators of abnormalities, failures and deteriorations. A technique for judging the state of an apparatus based on such indicators exists and is becoming popular as an equipment diagnosing technology. Such a technology is described, for example, by Toshio Sada, Shouzou Takada, et al. in an article with the title "The state of the Art and the Future of Equipment Diagnosing Technologies" written on pages 3 to 10 of a technical magazine "Measurement and Control", Vol. 25, No. 10 published in the year of 1988.
This diagnosing technique requires that equipment parameters clearly relevant to abnormalities and failures of the equipment be known in advance. Moreover, it is necessary to install sensors or the like which are not related directly to the operation of the equipment as means for reading the equipment parameters. When applying this diagnostic technique to the manufacturing of a semiconductor device, it is necessary to further specify parameters that are clearly related to abnormalities of the device.
By the way, in a process for creating a layer using a sputtering technique or a Chemical Vapor Deposition technique (referred to hereafter as a CVD technique) adopted in the manufacturing of semiconductor devices and in a dry etching technique and the like, a physical chemistry reaction works in an unequilibrium state utilizing a weak electrical current plasma. In order to sense the state of such a process, a probing technique is adopted. In the probing technique, a sensor that inadvertently causes disorder is typically installed. Such a sensor usually disturbs the reaction that should naturally work normally. In some cases, the sensor adversely gives rise to bad products. As such, this technique has shortcomings leading to impracticability.
Recently, manufacturing requirements are getting severe on the performance enhancement of semiconductor devices. Therefore, semiconductor processes tend to generate defective products due to device abnormalities. In order to cope with this problem, a countermeasure is taken by detecting abnormalities and failures of the equipment at an early stage. It is essential to reduce the number of bad products produced.
By the way, when diagnosing an equipment, it is necessary to specify parameters of the equipment as in the case with the conventional technique described above. However, there has been a problem caused by the fact that parameters relevant to abnormalities of the semiconductor manufacturing equipment are difficult to be specified clearly. This is because a diagnostic system for grasping phenomena indicating equipment abnormalities does not exist. Such phenomena can be used as a basis for detecting abnormalities of the equipment.